Terrazzo grinding apparatus



Nov. 2, 1937. w, MALL 2,097,730

TERRAZZO GRINDING APPARATUS Filed April 12,1935 2 Sheets-Sheet 1 Nov. 2, 1937; w MALL 2,097,730

TERRAZZO GRINDING APPARATUS Filed April 12, 1935 2 Sheets-Sheet 2 Patented Nov. 2, 1937 UNlTED STATES PATENT f OFFICE 2,097,736 TERRAZZO GRINDING APPARATUS Arthur William Mall, Chicago, 11. Application April 12, 1935, Serial No.'15,966

10 Claims. (01. 51-177) My invention relates to anew and useful improvement in apparatus for grinding terrazzo floors and like devices.

1 My invention relates more particularly to improvements in connection with supplying sand and water to the grinding wheel and other improvements in connection with the grinding wheel.

An object of the present invention is to pro vide an improved grinding, scrubbing or polish ing machine or like device. A further object is to provide an improved grinding, scrubbing or polishing machine of the class described capable of operating at a greatly increased rate of speed.

.A further object is to provide an improved machine of the class described which has means forchanging the position of the motor with respect to the grinding wheel so that more or less of the 20 weight of the frame and motor may be applied to compensate for the wear on the grinding wheel or for any other purpose.

A further object is to provide improved means i for supplying sand and water to the grinding 25 Wheel.

A further object is to provide such means capable of operation to supply a desired quantity of sand and water operated by the action of the grinding wheel.

A further object is to provide an improved construction of grinding wheel and head.

A further object is to provide the same so constructed that grinding wheels may be removed or changed with a minimum amount of labor or inconvenience.

A further object is to provide an improved mounting for grinding wheels in mechanism of the character described, whereby the grinding wheels can be easily and quickly changed in the event that one becomes broken or worn out.

Other objects and advantages will be more apparent from the following description, wherein reference is had to the accompanying two sheets 45 of drawings upon which:

Fig. l is a side elevational view of my improved apparatus; v

Fig. 2 is a vertical sectional view of the grind- Ving wheel carrier, driving head and sand hopper; and

Fig. 3 is a perspective view of the grinding wheel, removed from the apparatus.

My invention will be described withparticular .reference to Patent- No. 1,980,491on Terrazzo 5 grinding apparatus issued November 13, 1934,

upon whichthis application provides improvements in certain meohanism thereof.

The motor 10 may be of the special type of heavy-duty motor that is vapor and dust-proof, and which is capable of approximately double momentary overload so that by furnishing a 7 1 H. P. motor-for a specific duty, 2. double momentary overload. may be obtained without injuring the same. Themotor l0 may carry at its forward enda bracket 20 which is securely bolted thereto 10 andin which a cross shaft 22 may be supported adjacent the lower end of the motor. A pair of arms '24 may extend rearwardly from the bracket 20 and carry at their rearward ends stub shafts 26 upon which support wheels 28 are adapted to be mounted. The wheels 28 may be provided with rubber tire portions which provide a better and firmer grip upon the floor during the operation of the machine, and for the further purpose of eliminating any possibility of marring or scratching the floor surface.

The motor l0 may carry directly thereabove a tank or water reservoir 32 and may support the same by aplurality of strap members 34 which extend upwardly from suitable positions upon thecasing of the motor In. The cover for the reservoir32-may have abuilt-in funnel and ascreen,.(not shown) and have an outlet adjacent its lower edge controlled by a' valve member 38. A flexible. hose 40 may extend forward from the valve 38 to the sand hopper 42 to the top of which the same may be connected by a suitable clamp member 44.

The sand hopper 42 may be suitably mounted upon the upper cover plate 46 of the driving head I4, having a shoulder 48 which rests upon the upper surface 50 thereof. I provide a slot 52 to cooperate with a pin 54 in the side of the part 46- to prevent rotation of the hopper 42. The hopper may be further provided with the funnelshaped bottom wall-56 within which a centrally located outlet vopening 58 is formed. A screen member 60 may be positioned within the hopper upon a suitable shoulder 6! provided for this purpose. A pipe member 62 may engage in outlet opening 58 of the hopper 42 and extend downwardly through hollow spindle 83 and terminate adjacent the lower end thereof. Means for suppo-rtingthe spindle housing M are provided in the form of a resilient construction which may include the leaf spring members H35 that extend forward from the motor support frame 2! The forward end of spring members I65 may be secured. to .a-ring member I E16 which is in turn connected to a flexible ring member I01 that is fastened at its inner edge I08 to a collar I09 mounted on the outside of housing M.

The grinding wheel I6 is adapted to be driven through the flexible shaft I2 which may be of any desired type and suitably connected to the motor shaft. The shaft I2 engages the stub shaft 14 in the grinding head l4 and is drivingly connected thereto.

The spindle housing 14 as best shown in Fig. 2 may contain the shaft member 14 and provides a suitable bearing in the form of ball bearing members ES and 80 to support the same therein.

The shaft 74 may carry at its forward end a bevel gear 8| which in turn meshes with a vertically disposed bevel gear 82 that is keyed to a spindle 83. The spindle 83 may have a suitable bearing 84 adjacent its upper end in the housing l4, and may have a pair of ball bearing support members 8'5 and 86 adjacent its lower end.

The spindle 83 is formed with a tubular passage way 88 within which the pipe member 62 is adapted to be positioned. The pipe member 62 is securely mounted in the lower end of hopper 42.

The spindle 83 may be provided with righthand screw threads at its lower end and engage a backing plate 92 fastened to the grinding wheel it. The grinding wheel l6 may be of any suitable hard material such as carborundum or other suitable grinding substance.

From the foregoing description it will be apparent that a suitable flexible drive for the grinding wheel it has been provided extending from the motor Ill.

In order to facilitate the removal of grinding wheel Hi from spindle 83, I provide a nut member 8311 adjacent the upper end of spindle 83. The nut member 830, is securely held in position after being screw threadedly mounted upon the spindle by a collar member 83b which is also screw threadly mounted upon a reduced portion of the spindle 83. The nut member 830! and the portion of the screw threaded spindle it engages are provided with left hand threads.

With this construction it can be seen that by ;removing the hopper 42 and applying a 'wrench or other suitable device to the nut member 830.,

the spindle will be rigidly held and the grinding wheel l6 may be unscrewed from the lower end of the spindle. It will thus be apparent that it is not necessary to turn the driving head on its side or upside down in order to remove the grinding wheel.

In the use of my improved terrazzo grinding apparatus it is very important that water and sand be fed to the lower surface of the grinding wheel. The grinding wheel is adapted to be driven at a comparatively high rate of speed such as 3500 R. P. M. and it is necessary to provide a continuous feed of sand and water in order to assist in the grinding down operation,

I have found that by providing a continuous feed of sand and water, that the amount of time required to grind down and polish a given surface can be greatly reduced from the time required when this is not done. In operation I have found that by placing a supply of sand in the hopper 42 and permitting a continuous stream of water to flow from the reservoir 32 through conduit ill into hopper 42 that the vibration and shaking down effect of the grinding wheel upon the surface provides the necessary force for shaking down through the hopper and into pipefmember 62 a continuous stream of sand and water. This result is achieved because of the floating manner in which the head I4 is supported and thus any and all vibration set up by the action of the high speed grinding Wheel is transmitted to the hopper.'

Beside terrazzo surface grinding I have found that with my improved method of feeding sand and water to the grinding wheel that many other uses may be found for the grinding apparatus. For example, the same may be employed for the purpose of power grouting in the surfacing of highways and for the removal of bumps on concrete pavements, and to grind down any pavements which are uneven. After a surface has been cut down to the level desired and in order to obtain a finished surface, I provide a mixture of fine sand and cement in the hopper 42 and by operating the apparatus rub in or power grout this material to fill up the air holes and uneven surfaces and make a surface smooth and level.

The physical effort necessary to rub in the particles of cement and sand to seal the surface is considerable and While this operation has here;

tofore been done by hand power only, it is believed to be obvious that by the use of the power device shown a much better and more efficient job of rubbing in can be accomplished. With the method described, the pores of the pavement, are closed much more satisfactorily than by any; hand method, and therefore this particular surface conditioning method is better than any other employed, and has the effect of making that. part of the highway which has been worked United States is:

1. The combination in a terrazzo grindingmachine of a horizontally disposed 'motor, a fluid supply associated therewith, a wheeled support secured to said motor, a flexible shaft extendin from said motor, a spindle driven thereby, a housing therefor, a universally tiltable face grinding wheel at the end of said spindle, a pair of cantilever spring members for supporting the same, a sand hopper mounted above said grindin wheel on said spindle housing, a conduit from said fluid supply to said sand hopper, and a conduit extending from the lower end of said hopper to the center of said grinding wheel.

2. The combination in a terrazzo grinding machine of a horizontally disposed motor, a fluid supply associated therewith, a wheeled support secured to said motor, a flexible shaft extending from said motor, a spindle driven thereby, a housing therefor, a universally tiltable face grinding wheel at the lower end of said spindle, a spring member extending from said motor and supporting said spindle housing, a sand hopper mounted above said grinding wheel on said spindle housing, a conduit from said fluid supply to said sand hopper, and a conduit extending from the lower end of said hopper to the center of said grinding wheel.

3. The combination in a terrazzo grinding ma,- chine of a horizontally disposed motor, a fluid supply associated therewith, a wheeled support secured to said motor, a flexible shaft extending Rather, what I desire to secure and protect by Letters Patent of the that sand therein is fed downwardly to said grinding wheel by the vibration caused by the revolving thereof.

4. The combination in a terrazzo grinding machine of a horizontally disposed motor, a fluid supply associated therewith, a wheeled support secured to said motor, a flexible shaft extending from said motor, a hollow vertical spindle driven thereby, a housing for said spindle, a universally tiltable face grinding wheel at the end of said spindle, a pair of cantilever spring members for supporting said housing and spindle, a conduit from said fluid supply, a sand hopper positioned on said housing above said hollow vertical spindle, said fluid conduit being connected therewith and a conduit extending from the lower end of said hopper to the center of said grinding wheel.

5. The combination in a terrazzo grinding machine of a horizontally disposed motor, a fluid supply associated therewith, a Wheeled support secured to said motor, a flexible shaft extending from said motor, a hollow vertical spindle driven thereby, a grinding head, said spindle being mounted therein, a universally tiltable face grinding wheel at the end of said spindle, a pair of spring members for supporting the same, a conduit from said fluid supp yra sand hopper positioned on said grinding head above said hollow vertical spindle, said fluid conduit connected therewith and a conduit extending from the lower end of said hopper through said hollow spindle to the center of said grinding wheel.

6. Apparatus of the class described, comprising a universally mounted grinding head, a hollow spindle therein, a grinding wheel secured to the lower end thereof, a sand hopper positioned on said grinding head, a source of water connected thereto and a conduit extending downwardly to said grinding wheel whereby sand and water in said hopper are gradually fed to said grinding wheel by the vibration of said unit when said grinding wheel is revolving.

7. Apparatus of the class described, comprising a universally mounted grinding head, a hollow spindle therein, a grinding wheel secured to the lower end thereof, a removable cylindrical sand hopper positioned on said grinding head, a source of water connected thereto, and a conduit extending downwardly to said grinding wheel through said hollow spindle whereby sand and water in said hopper are gradually fed to said grinding wheel by the vibration of said unit when said grinding wheel is revolving.

8. Apparatus of the class described, comprising a universally grinding head, a hollow vertical spindle therein, a motor, a flexible drive from said motor to said spindle, a grinding wheel secured to the lower end thereof, a sand hopper positioned on said grinding head, a source of water connected thereto, and a conduit extending downwardly through said hollow spindle to said grinding wheel whereby sand and water in said hopper are gradually fed to said grinding wheel by the vibration of said unit when said grinding wheel is revolving.

9. The combination with a terrazzo grinding apparatus having a universally mounted grinding head, a hollow spindle and a grinding wheel secured to the lower end thereof, of a hopper removably mounted on said grinding head above said hollow spindle, said hopper being adapted to receive a supply of sand and water and a tubular passageway extending downwardly from said hopper to the center of said grinding wheel.

10. The combination with a terrazzo grinding apparatus having a universally mounted grinding head, a hollow vertical spindle and a grinding wheel secured to the lower end thereof, of a hopper removably mounted on said grinding head above said hollow spindle, said hopper being adapted to receive a supply of sand and water and a tubular passageway extending downwardly through said vertical spindle from said hopper to the center of said grinding wheel.

ARTHUR WILLIAM NIALL. 

